Metallic silicon production smelting furnace

Abstract

The utility model relates to a metal silicon production smelting furnace which comprises a heat preservation shell, a guide cylinder arranged in the heat preservation shell, a heating device arranged below the guide cylinder, a smelting crucible arranged in the heating device and a driving mechanism arranged below the smelting crucible and driving the smelting crucible to rotate. The vacuumizing pump is arranged on the outer side of the heat preservation shell, and an exhaust pipe of the vacuumizing pump is communicated with the heat preservation shell; the heating device comprises a plurality of graphite heating rings arranged on the outer side of the smelting crucible in a sleeving mode, a PID temperature controller for controlling the graphite heating rings and an infrared radiation pyrometer arranged in the heat preservation shell and used for detecting the temperature in the smelting crucible. According to the heating device, a plurality of graphite heating rings are combined into a barrel shape to heat the smelting crucible in the heating device, and accurate temperature control over different areas in the smelting furnace can be achieved by independently controlling each annular graphite heating body.

Description

Technical Field

[0001] The utility model belongs to the technical field of metal silicon melting equipment, and particularly relates to a metal silicon production melting furnace. Background Art

[0002] Metallic silicon, also known as industrial silicon or crystalline silicon, is usually a product prepared by reducing silica (mainly composed of SiO2) with a carbonaceous reducing agent (such as petroleum coke, charcoal, wood blocks, low-ash coal, etc.) at high temperature. The content of the main component silicon element is usually about 98%, and there are also high-purity products with a content as high as 99.99%. The main uses of metallic silicon include being used as an additive for non-ferrous base alloys, and as the starting material for producing semiconductor silicon and organosilicon. The melting furnace is the equipment for initially producing metallic silicon. The melting furnace mainly consists of a power supply system, a melting system, a cooling system, a gas collecting and exhaust system, a feeding system, a furnace body, and other parts. The feeding system puts silicon raw materials and reducing agents into the melting system. Under the action of high temperature, the silicon raw materials are reduced to molten silicon. Subsequently, the crystal pulling device takes out the crystallized metallic silicon in the form of silicon rods, or the molten metallic silicon is discharged from the melting furnace and cast into products of required shapes. The cooling system is used to regulate the temperature inside the melting furnace, and the gas collecting and exhaust system collects and processes the harmful gases generated during melting.

[0003] The heating element used in the existing melting furnace is an integral body. The integral heating element heats the entire melting crucible and cannot perform local heating, so it is impossible to achieve precise temperature control of different regions inside the melting furnace. Adopting the local heating method helps to reduce the temperature gradient and improve the uniformity of the melting process. Summary of the Utility Model

[0004] In order to overcome the problems existing in the background art, the utility model provides a metal silicon production melting furnace, including: a heat preservation outer shell, a flow guiding cylinder arranged inside the heat preservation outer shell, a heating device arranged below the flow guiding cylinder, a melting crucible arranged inside the heating device, a driving mechanism arranged below the melting crucible and driving the melting crucible to rotate, and a vacuum pump arranged outside the heat preservation outer shell and communicated with the heat preservation outer shell through an air extraction pipe; the heating device includes: a plurality of graphite heating rings sleeved outside the melting crucible, a PID temperature controller for controlling the graphite heating rings, and an infrared radiation pyrometer arranged inside the heat preservation outer shell and detecting the temperature inside the melting crucible.

[0005] Furthermore, a tubular heat insulation layer is arranged inside the heat preservation outer shell, and the graphite heating rings are arranged on the inner side of the heat insulation layer.

[0006] Furthermore, a sliding rod penetrating into the heat preservation outer shell is arranged on the side wall of the heat preservation outer shell, the infrared radiation pyrometer is arranged at the end of the sliding rod, and a length scale is arranged on the side wall of the sliding rod.

[0007] Further, the driving mechanism includes: a bearing ring disposed at the upper end of the heat insulation layer and sleeved on the upper edge of the melting crucible, a support shaft disposed on the lower bottom surface of the melting crucible, a support disk disposed in the heat preservation housing, a first transmission shaft rotatably disposed at the center of the support disk and connected to the support shaft, a bearing disposed at the bottom end of the heat preservation housing and supporting the lower end of the first transmission shaft, a first bevel gear disposed on the first transmission shaft, a second bevel gear meshing with the first bevel gear, a second transmission shaft meshing with the second bevel gear to form a transmission connection and rotatably passing through the side wall of the heat preservation housing, a reduction gearbox connected to the other end of the second transmission shaft, and an electric motor driving the reduction gearbox.

[0008] Further, the first transmission shaft and the support shaft are connected by a flange.

[0009] Further, the inner wall and the bottom of the melting crucible are provided with raised stripes.

[0010] Further, a three-way pipe is provided on the side wall of the heat preservation housing. A first electromagnetic valve is provided on the first branch pipe of the three-way pipe, a second electromagnetic valve is provided on the second branch pipe of the three-way pipe, and a pressure sensor is provided on the side wall of the heat preservation housing.

[0011] Further, a sealing cover is provided at the opening at the upper end of the heat preservation housing.

[0012] The beneficial effects of the present utility model:

[0013] Compared with the prior art, the heating device of the present utility model combines multiple graphite heating rings into a cylindrical shape to heat the internal melting crucible. By separately controlling each ring-shaped graphite heating element, precise temperature control of different regions in the melting furnace can be achieved. This local heating method helps to reduce the temperature gradient and improve the uniformity of the melting process. When the temperature needs to be adjusted, the separately controlled heating elements can respond quickly to make the temperature reach the set value, thereby improving the melting efficiency and product quality. By reducing the power of the heating elements in the areas where high temperature is not required and increasing the power in the areas where high temperature is required, energy waste can be effectively reduced and energy utilization efficiency can be improved. The modular design of the ring-shaped graphite heating elements makes replacement and maintenance more convenient. When a certain heating element fails, it can be replaced separately without stopping the furnace to repair the entire heating element system.

[0014] In addition, compared with the prior art, the driving mechanism of the present utility model generates a rotational driving force downward to rotate the melting crucible, and raised stripes are provided inside the crucible to assist in stirring the molten metal silicon, making the molten metal silicon heated evenly during the melting process. At the same time, this stirring structure does not require a stirring device at the deflector cylinder, saving the internal space of the melting furnace and making the driving mechanism no longer an obstacle to the crystal pulling device and the feeding device. Description of the Drawings

[0015] Figure 1 It is a schematic structural diagram of a smelting furnace for producing metallurgical silicon;

[0016] Figure 2 It is a schematic cross-sectional structural diagram of a smelting furnace for producing metallurgical silicon;

[0017] Figure 3 It is a schematic top view structural diagram of a smelting crucible.

[0018] In the figure: heat preservation outer shell 1, flow guiding cylinder 2, smelting crucible 3, exhaust pipe 4, exhaust vacuum pump 5, graphite heating ring 6, infrared radiation pyrometer 7, heat insulation layer 8, bearing ring 9, support shaft 10, sliding rod 11, support plate 12, first transmission shaft 13, bearing 14, first bevel gear 15, second bevel gear 16, second transmission shaft 17, reduction gearbox 18, motor 19, flange 20, stripe 21, three-way pipe 22, first branch pipe 23, first solenoid valve 24, second branch pipe 25, second solenoid valve 26, air pressure sensor 27, sealing cover 28. Detailed Embodiment

[0019] In order to make the purpose, technical solutions and beneficial effects of the present utility model clearer, the preferred embodiments of the present utility model will be described in detail below to facilitate understanding by those skilled in the art.

[0020] Please refer to Figures 1 to 3 , the present utility model provides a smelting furnace for producing metallurgical silicon, including: a heat preservation outer shell 1, a flow guiding cylinder 2 arranged inside the heat preservation outer shell 1, a heating device arranged below the flow guiding cylinder 2, a smelting crucible 3 arranged inside the heating device, a driving mechanism arranged below the smelting crucible 3 and driving the smelting crucible 3 to rotate, and an exhaust vacuum pump 5 arranged outside the heat preservation outer shell 1 and communicated with the heat preservation outer shell 1 through an exhaust pipe 4; the heating device includes: a plurality of graphite heating rings 6 sleeved outside the smelting crucible 3, a PID temperature controller for controlling the graphite heating rings 6, and an infrared radiation pyrometer 7 arranged inside the heat preservation outer shell 1 and detecting the temperature inside the smelting crucible 3.

[0021] The flow guiding cylinder 2 is in a conical shape with a wider upper part and a narrower lower part, and its functions are as follows:

[0022] 1. Optimize temperature distribution: The flow guiding cylinder 2 can effectively affect the temperature distribution of the crystal interface, making the heat more concentrated and effectively transferred to the molten silicon, thereby reducing the heating energy consumption and improving the smelting efficiency. At the same time, by optimizing the temperature gradient, the micro-defects inside the crystal can also be reduced, improving the quality of the crystal.

[0023] 2. Improve production stability and safety: The draft tube 2 helps to stabilize the smelting process and reduce production accidents caused by temperature fluctuations or unstable flows. At the same time, it can also improve the production efficiency and economic benefits of the entire production line.

[0024] In this embodiment, the material of the melting crucible 3 is selected as a graphite crucible.

[0025] In this embodiment, the infrared radiation pyrometer 7 selected is: Fluke 568 infrared radiation thermometer.

[0026] A tubular heat insulation layer 8 is provided inside the heat preservation shell 1, and the graphite heating ring 6 is arranged on the inner side of the heat insulation layer 8. The heat insulation layer 8 is a refractory castable, which is made of refractory aggregates, powders and binders in a certain proportion. It can keep warm and insulate heat, protect the furnace body and reduce energy consumption.

[0027] A sliding rod 11 is provided on the side wall of the heat preservation shell 1 and penetrates into the heat preservation shell 1. The infrared radiation pyrometer 7 is arranged at the end of the sliding rod 11, and a length scale is provided on the side wall of the sliding rod 11. The sliding rod 11 has a part remaining outside the heat preservation shell 1. The sliding rod 11 supports the infrared radiation pyrometer 7 and makes the infrared radiation pyrometer 7 face the molten metallurgical silicon. When feeding materials and pulling single crystals, the sliding rod 11 is pulled outwards to prevent the infrared radiation pyrometer 7 from hindering the feeding and pulling of single crystals. It goes without saying that the sliding rod 11 is in close contact with the side wall of the heat preservation shell 1 and no gas leakage will occur.

[0028] The driving mechanism includes: a bearing ring 9 provided at the upper end of the heat insulation layer 8 and sleeved on the upper edge of the melting crucible 3, a support shaft 10 provided on the lower bottom surface of the melting crucible 3, a support disk 12 provided inside the heat preservation shell 1, a first transmission shaft 13 rotatably provided at the center of the support disk 12 and connected to the support shaft 10, a bearing 14 provided at the bottom end of the heat preservation shell 1 and supporting the lower end of the first transmission shaft 13, a first bevel gear 15 provided on the first transmission shaft 13, a second bevel gear 16 meshing with the first bevel gear 15, a second transmission shaft 17 meshing with the second bevel gear 16 to form a transmission connection and rotatably passing through the side wall of the heat preservation shell 1, a reduction gearbox 18 connected to the other end of the second transmission shaft 17, and a motor 19 driving the reduction gearbox 18. The function of the bearing ring 9 is to support the stable rotation of the melting crucible 3 without friction with the inner wall of the graphite heating ring 6. The motor 19 drives the reduction gearbox 18, the reduction gearbox 18 drives the second transmission shaft 17, the second transmission shaft 17 drives the first transmission shaft 13, and the first transmission shaft 13 drives the support shaft 10 and the melting crucible 3 to rotate. The motor 19 includes a controller to make the melting crucible 3 rotate forward and backward to increase the stirring effect. It goes without saying that a rotary seal structure is provided between the second transmission shaft 17 and the mounting hole on the side wall of the heat preservation shell 1.

[0029] The first transmission shaft 13 and the support shaft 10 are connected by a flange 20. The flange 20 facilitates the disassembly of the melting crucible 3.

[0030] The inner wall and bottom of the melting crucible 3 are provided with raised stripes 21. The stripes 21 enhance the stirring effect on the molten metal during rotation.

[0031] A tee pipe 22 is provided on the side wall of the heat preservation shell 1. A first electromagnetic valve 24 is provided on the first branch pipe 23 of the tee pipe 22, a second electromagnetic valve 26 is provided on the second branch pipe 25 of the tee pipe 22, and a pressure sensor 27 is provided on the side wall of the heat preservation shell 1. The tee pipe 22 mainly cooperates with the vacuum pump 5. When the first electromagnetic valve 24 and the second electromagnetic valve 26 are both closed, the vacuum pump 5 can extract the air in the melting furnace, reducing the oxygen content during the melting process, thereby improving the purity of metallurgical silicon. The first branch pipe 23 can be connected to an inert gas tank to further enhance the stability of the furnace. At the same time, the second branch pipe 25 can be connected to a gas at an appropriate temperature to adjust the temperature inside the heat preservation shell 1. The vacuum pump 5 can also extract the harmful gases generated during melting.

[0032] A sealing cover 28 is provided at the upper opening of the heat preservation shell 1. The sealing cover 28 can be opened during feeding and crystal pulling, and the melting crucible 3 can also be cleaned by opening the sealing cover 28 after melting is completed.

[0033] The material of the heat preservation shell 1 is preferably a combination of a stainless steel outer layer and a silicate refractory material lining.

[0034] This metallurgical silicon production melting furnace also includes a PLC controller, which controls each component and the motor 19 included in this metallurgical silicon production melting furnace, and performs parameter setting and parameter viewing.

[0035] When this utility model is in use: First, turn on the heating device to preheat the furnace. After the preheating is completed, open the sealing cover 28 and place silica and a reducing agent into the melting crucible 3 through the middle of the guide cylinder 2 and cover the sealing cover 28. Start the vacuum pump 5 to extract the air in the heat preservation shell 1, and introduce inert gas through the tee pipe 22 if necessary. Start the melting program, and control the melting temperature via the PID temperature controller and the infrared radiation thermometer. During this period, start the motor 19 to rotate the melting crucible 3 to stir the molten metallurgical silicon. During melting, use the vacuum pump and the tee pipe 22 to cooperate for temperature adjustment. After melting is completed, extract the waste gas generated in the heat preservation shell 1 and transport it to the waste gas treatment equipment. When the temperature drops to the crystal pulling temperature, open the sealing cover 28 to introduce the crystal pulling equipment and perform crystal pulling through the guide cylinder 2. During this period, the PID temperature controller controls the graphite heating ring 6 separately to form a favorable temperature gradient. After crystal pulling is completed, clean the melting crucible 3 to prepare for the next metallurgical silicon melting.

[0036] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in terms of form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A metal silicon production smelting furnace, characterized in that, Including: A thermal insulation housing (1), a flow guide cylinder (2) disposed within the thermal insulation housing (1), a heating device disposed below the flow guide cylinder (2), a melting crucible (3) disposed within the heating device, a driving mechanism disposed below the melting crucible (3) and driving the melting crucible (3) to rotate, and a vacuum pump (5) disposed outside the thermal insulation housing (1) and having an air extraction pipe (4) communicating with the thermal insulation housing (1); the heating device includes: a plurality of graphite heating rings (6) sleeved outside the melting crucible (3), a PID temperature controller controlling the graphite heating rings (6), and an infrared radiation pyrometer (7) disposed within the thermal insulation housing (1) and detecting the temperature within the melting crucible (3).

2. The metal silicon production smelting furnace according to claim 1, wherein: A tubular heat insulation layer (8) is disposed within the thermal insulation housing (1), and the graphite heating rings (6) are disposed inside the heat insulation layer (8).

3. A metal silicon production smelting furnace according to claim 2, characterized in that: A sliding rod (11) penetrating into the thermal insulation housing (1) is disposed on the side wall of the thermal insulation housing (1), the infrared radiation pyrometer (7) is disposed at the end of the sliding rod (11), and a length scale is disposed on the side wall of the sliding rod (11).

4. A metal silicon production smelting furnace according to claim 2, characterized in that, The driving mechanism includes: a bearing ring (9) disposed at the upper end of the heat insulation layer (8) and sleeved on the upper edge of the melting crucible (3), a support shaft (10) disposed on the lower bottom surface of the melting crucible (3), a support disk (12) disposed within the thermal insulation housing (1), a first transmission shaft (13) rotatably disposed at the center of the support disk (12) and connected to the support shaft (10), a bearing (14) disposed at the bottom end of the thermal insulation housing (1) and supporting the lower end of the first transmission shaft (13), a first bevel gear (15) disposed on the first transmission shaft (13), a second bevel gear (16) meshing with the first bevel gear (15), and a second transmission shaft (17) meshing with the second bevel gear (16) to form a transmission connection and rotatably passing through the side wall of the thermal insulation housing (1). A reduction gearbox (18) connected to the other end of the second transmission shaft (17), and a motor (19) driving the reduction gearbox (18).

5. A metal silicon production smelting furnace according to claim 4, characterized in that, A flange plate (20) is provided for connecting the first transmission shaft (13) and the support shaft (10).

6. A metal silicon production smelting furnace according to claim 4, characterized in that, Raised stripes (21) are provided on the inner wall and bottom of the melting crucible (3).

7. A metal silicon production smelting furnace according to claim 1, characterized in that, A three-way pipe (22) is provided on the side wall of the thermal insulation housing (1), a first electromagnetic valve (24) is provided on the first branch pipe (23) of the three-way pipe (22), a second electromagnetic valve (26) is provided on the second branch pipe (25) of the three-way pipe (22), and a pressure sensor (27) is provided on the side wall of the thermal insulation housing (1).

8. A metal silicon production melting furnace according to claim 1, characterized in that, A sealing cover (28) is provided at the open upper end of the thermal insulation housing (1).

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